The present invention relates to an attitude angle sensor correcting apparatus for correcting measured attitude angle data, which is output from an attitude angle sensor mounted on an artificial satellite, with an estimated attitude angle derived from geographical image data.
A conventional attitude angle sensor correcting apparatus for a satellite application includes an attitude angle sensor data memory and an attitude angle sensor noise corrector. The attitude angle sensor noise corrector produces an attitude angle correction signal by using measured attitude angle data read out of the attitude angle sensor data memory. The prerequisite with the attitude angle sensor correcting apparatus is that a positional relation between an attitude angle sensor and the center of gravity of a satellite on which it is mounted is precisely measured and is strictly controlled even in the space. When an error (alignment error) occurs in the attitude angle sensor due to some cause, sensor correction accuracy is critically lowered. Moreover, because a reference value for correcting alignment errors is not available, the detection of alignment errors itself is not practicable.
Technologies relating to the present invention are disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 59-229667, 1-237411, 7-329897 and 11-160094 as well as in Japanese Patent Publication No. 61-25600.
It is therefore an object of the present invention to provide an attitude angle sensor correcting apparatus capable of shooting tridimensionally a plurality of GCPs (Ground Control Points) located on the ground with, e.g., a camera, producing estimated satellite attitude data from measured GCP values and true GCP values, and correcting measured attitude angle data with the estimated attitude data to thereby correct attitude angle sensor data.